Subject: Re: 4 port ethernet cards
To: Jonathan Stone <jonathan@DSG.Stanford.EDU>
From: D'Arcy J.M. Cain <>
List: current-users
Date: 01/31/1998 08:55:07
Thus spake Jonathan Stone
> Excuse me for butting in, but why are there three parallel links from
> your NetBSD box to this hub?  In the normal case the hub is all one
> Ethernet domain.

I know.

> The configuration you drew makes no sense to me at all.  Unless the
> hub is a switching hub configured with three distinct VLANs, one for
> each link from the NetBSD box, you might as well put the external
> boxes A, B, and C directly onto the hub, with just one link from the
> NetBSD box to the hub. I cant see how the two additional links are
> achieving anything useful in your topology.

Ok, first, it isn't "my" topology.  Here's what happened.  Someone
was lending us the 4 port card so we could try it out temporarily.
He brought it down with extra cables.  Unfortunately he didn't have
twisted ethernet cables but he did have an extra hub so he set up
the topology I described assuring me that, except for the fact that
it didn't really segment the network, it would work just like having
proper twisted cables.  The idea was that we would go out the next
day and get proper twisted cables and remove the hub from the loop.

> I havent looked at Matt's driver in ages, but it's just barely
> possible that the autosense is consistently sending packets out each
> port of the multiport card, close enough togehter in time that they
> _always_ collide and so _always_ fail to autosense.  Or alternatively,
> switching the PHY chips to 10Mbit could be confusing the hub for long
> enough to break autosense on the other ports of the multiport card.

Yes, I was thinking along those lines myself.  I was trying to get
some support for the idea that the hub kluge was the problem so I
could get him to bring it back and try it with proper cables.  I
wouldn't care but he's probably going around now telling everyone
that NetBSD doesn't work.  I can't have that, now can I?

D'Arcy J.M. Cain <darcy@{druid|vex}.net>   |  Democracy is three wolves                |  and a sheep voting on
+1 416 424 2871     (DoD#0082)    (eNTP)   |  what's for dinner.